The invention relates to a motor vehicle door lock with a lock latch and a detent pawl, preferably with a driving journal attached to the detent pawl and used to actuate the detent pawl, with a lock mechanism with a base plate, an inner release lever, an outer release lever, an inner safety lever, an outer safety lever coupled with inner safety lever, a central lock lever acting on the inner safety lever and on the outer safety lever and able to be connected to a central lock drive and, preferably, with a transmission lever and, wherein if a transmission lever is present, the movement of the inner release lever and of the outer release lever is transmitted by the transmission lever to the detent pawl or to a driving journal and, in any case, wherein the outer safety lever and, preferably, also the inner safety lever is or are stopped in the release position when the lock latch and detent pawl are open.
The known motor vehicle door lock on which the invention is based (German-C 3 220 705) has a transmission lever that is mounted, single-armed, to pivot approximately centrally on the outer release lever. The transmission lever has a link slot extending axially approximately along the angle of incidence of the catch pawl, a link slot in which an attachment, bent at a right angle, of the outer safety lever engages as a sliding block. When the outer safety lever, which, moreover, is coupled to move with the inner safety lever by a plug connection, is actuated, the transmission lever is pivoted back and forth, but the linking connection simultaneously makes possible a translational movement of the transmission lever when the outer release lever is actuated. At its exposed end, the transmission lever is provided with an outwardly cleanly cut, slotlike coupling opening whose longitudinal axis also extends in the axial direction of the transmission lever. The cleanly cut area of the coupling opening is delimited by a crossbar projecting crosswise to the angle of incidence and by a lengthwise bar projecting approximately in the angle of incidence, between which a passage is made. If the here-present driving journal of the detent pawl is at the height of the passage, then the transmission lever can be pivoted by the outer safety lever or by the inner safety lever. On the other hand, when the lock latch and detent pawl are open, the driving journal is in the undercut area of the coupling opening. In this case, the transmission lever cannot be pivoted. It thus stops, in this condition, the movement of the outer safety lever and of the inner safety lever, which thus are stopped in this condition in the released position.
With the above-explained design it is achieved that, when the driver's door is open, the driver's door cannot be secured from the inside by locking or by pressing the door button, because otherwise the danger exists that the motor vehicle would become locked with the door key lying in the motor vehicle.
The above-explained motor vehicle door lock also has the possibility of letting a central locking drive engage, with the help of a central lock lever, in the outer safety lever and in the inner safety lever.
With multistep locking, as is increasingly being required in central locks, there arise with the above-explained, known motor vehicle door lock, the problem that the stopping of the outer safety lever and of the inner safety lever, when the lock latch and detent pawl are open, also acts relative to the central lock drive when the latter is activated, for example, by the paasenger door or by the trunk lid, toward the safety position. Here, an electronic memory circuit can be provided that stores the switching command for the central lock drive of the motor vehicle door lock of the door that is still open. This however, is rather expensive and not as reliable as conventional mechanical means.